This invention relates to apparatus for the separation of low density fluids from higher density fluids or particles or both and more particularly to self-contained apparatus in which initial separation, coalescing and filtration steps are carried out substantially in series and in that order.
Self-contained devices for the separation of solid particulate matter and high density fluids such as water from lower density fluids such as oil, kerosene, diesel fuel, gasoline and even air, have been devised heretofore in which separation, coalescing, and filtration action have occurred. However, in such prior art devices, such actions have been carried out more or less simultaneously and often without adequate provision for one or more of such actions. In particular, the initial separation of fluids has not been adequately provided for or accomplished in the prior art.
It will be understood that "initial separation" action comprises the removal of large particles and droplets of high density fluids that may be entrained in the flow of the mixture of fluids and which, if not separated out, tend to be collected on the leading surface of the filter means, due to their size, requiring frequent replacement or cleaning of the filter means. "Coalescing" action is the formation of large droplets of high density fluid due to the capture of smaller droplets by larger droplets. Such action is a function of the surface tension of the high density fluid and is sometimes referred to as "beading" action. Finally, "filtration" action is the straining of the lower density fluid to physically remove higher density fluids and particles by means of a filter element.
In general, prior art devices of interest have comprised a hollow chamber providing a sediment bowl at the bottom and containing a replaceable filter element at the top. The fluid is introduced into the bottom of the chamber and allowed to percolate upwardly and through the filter element to an outlet at the top of the chamber.
U.S. Pats. No. 2,543,481 to Wicks et al. and No. 2,486,389 to Clark are representative of such prior art devices. In the operation of such devices the higher density fluids and particles are expected to gravitate into the bottom of the sediment bowl where they may be drained from the system.
However, in actual practice, the constant flow of fluid into the bottom of such prior art devices tends to re-entrain a substantial portion of the fluids and particles which settle into the sediment bowl before they can be drained, carrying them to the leading surface of the filter element where they are collected, thus tending to clog the filter and require its early replacement. It will be understood that, in such prior art devices, there is essentially no initial separation action other than in conjunction with whatever coalescing action may occur at the leading surface of the filter element or elsewhere in the device.
In U.S. Pat. No. 3,187,893 to Poll et al., a device is disclosed in which an attempt is made to provide coalescing action in a portion of the device physically distinct from the filtration element. However, no provision whatever is made for initial separation prior to the coalescing element thereof which element is a coarse filter that is subject to clogging by large particles entrained in the incoming fluids.
The device disclosed in U.S. Pat. No. 3,428,180 to Rogers represents an entirely different approach to the problem and is a great improvement over the prior art. However, it has been found that even greater improvement over the prior art may be obtained by providing an initial separation action and by physically dividing the initial separation, coalescing and filtration action from each other so that these actions occur in series and in that order in accordance with the teaching of this invention.
Thus, it is an object of this invention to provide improved apparatus for the separation of low density fluids from higher density fluids or particles or both.
It is a further object of this invention to provide such apparatus in a self-contained and compact form which is convenient to install and maintain, simple and inexpensive to manufacture and yet more efficient in operation without frequent servicing.